tools/perf/util/probe-finder.c

   1 /*
   2  * probe-finder.c : C expression to kprobe event converter
   3  *
   4  * Written by Masami Hiramatsu <mhiramat@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  */
  21
  22 #include <sys/utsname.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <errno.h>
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <stdarg.h>
  32 #include <dwarf-regs.h>
  33
  34 #include <linux/bitops.h>
  35 #include "event.h"
  36 #include "dso.h"
  37 #include "debug.h"
  38 #include "intlist.h"
  39 #include "util.h"
  40 #include "symbol.h"
  41 #include "probe-finder.h"
  42
  43 /* Kprobe tracer basic type is up to u64 */
  44 #define MAX_BASIC_TYPE_BITS     64
  45
  46 /* Dwarf FL wrappers */
  47 static char *debuginfo_path;    /* Currently dummy */
  48
  49 static const Dwfl_Callbacks offline_callbacks = {
  50         .find_debuginfo = dwfl_standard_find_debuginfo,
  51         .debuginfo_path = &debuginfo_path,
  52
  53         .section_address = dwfl_offline_section_address,
  54
  55         /* We use this table for core files too.  */
  56         .find_elf = dwfl_build_id_find_elf,
  57 };
  58
  59 /* Get a Dwarf from offline image */
  60 static int debuginfo__init_offline_dwarf(struct debuginfo *dbg,
  61                                          const char *path)
  62 {
  63         int fd;
  64
  65         fd = open(path, O_RDONLY);
  66         if (fd < 0)
  67                 return fd;
  68
  69         dbg->dwfl = dwfl_begin(&offline_callbacks);
  70         if (!dbg->dwfl)
  71                 goto error;
  72
  73         dbg->mod = dwfl_report_offline(dbg->dwfl, "", "", fd);
  74         if (!dbg->mod)
  75                 goto error;
  76
  77         dbg->dbg = dwfl_module_getdwarf(dbg->mod, &dbg->bias);
  78         if (!dbg->dbg)
  79                 goto error;
  80
  81         return 0;
  82 error:
  83         if (dbg->dwfl)
  84                 dwfl_end(dbg->dwfl);
  85         else
  86                 close(fd);
  87         memset(dbg, 0, sizeof(*dbg));
  88
  89         return -ENOENT;
  90 }
  91
  92 static struct debuginfo *__debuginfo__new(const char *path)
  93 {
  94         struct debuginfo *dbg = zalloc(sizeof(*dbg));
  95         if (!dbg)
  96                 return NULL;
  97
  98         if (debuginfo__init_offline_dwarf(dbg, path) < 0)
  99                 zfree(&dbg);
 100         if (dbg)
 101                 pr_debug("Open Debuginfo file: %s\n", path);
 102         return dbg;
 103 }
 104
 105 enum dso_binary_type distro_dwarf_types[] = {
 106         DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
 107         DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
 108         DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO,
 109         DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
 110         DSO_BINARY_TYPE__NOT_FOUND,
 111 };
 112
 113 struct debuginfo *debuginfo__new(const char *path)
 114 {
 115         enum dso_binary_type *type;
 116         char buf[PATH_MAX], nil = '\0';
 117         struct dso *dso;
 118         struct debuginfo *dinfo = NULL;
 119
 120         /* Try to open distro debuginfo files */
 121         dso = dso__new(path);
 122         if (!dso)
 123                 goto out;
 124
 125         for (type = distro_dwarf_types;
 126              !dinfo && *type != DSO_BINARY_TYPE__NOT_FOUND;
 127              type++) {
 128                 if (dso__read_binary_type_filename(dso, *type, &nil,
 129                                                    buf, PATH_MAX) < 0)
 130                         continue;
 131                 dinfo = __debuginfo__new(buf);
 132         }
 133         dso__put(dso);
 134
 135 out:
 136         /* if failed to open all distro debuginfo, open given binary */
 137         return dinfo ? : __debuginfo__new(path);
 138 }
 139
 140 void debuginfo__delete(struct debuginfo *dbg)
 141 {
 142         if (dbg) {
 143                 if (dbg->dwfl)
 144                         dwfl_end(dbg->dwfl);
 145                 free(dbg);
 146         }
 147 }
 148
 149 /*
 150  * Probe finder related functions
 151  */
 152
 153 static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
 154 {
 155         struct probe_trace_arg_ref *ref;
 156         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 157         if (ref != NULL)
 158                 ref->offset = offs;
 159         return ref;
 160 }
 161
 162 /*
 163  * Convert a location into trace_arg.
 164  * If tvar == NULL, this just checks variable can be converted.
 165  * If fentry == true and vr_die is a parameter, do huristic search
 166  * for the location fuzzed by function entry mcount.
 167  */
 168 static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
 169                                      Dwarf_Op *fb_ops, Dwarf_Die *sp_die,
 170                                      struct probe_trace_arg *tvar)
 171 {
 172         Dwarf_Attribute attr;
 173         Dwarf_Addr tmp = 0;
 174         Dwarf_Op *op;
 175         size_t nops;
 176         unsigned int regn;
 177         Dwarf_Word offs = 0;
 178         bool ref = false;
 179         const char *regs;
 180         int ret, ret2 = 0;
 181
 182         if (dwarf_attr(vr_die, DW_AT_external, &attr) != NULL)
 183                 goto static_var;
 184
 185         /* TODO: handle more than 1 exprs */
 186         if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
 187                 return -EINVAL; /* Broken DIE ? */
 188         if (dwarf_getlocation_addr(&attr, addr, &op, &nops, 1) <= 0) {
 189                 ret = dwarf_entrypc(sp_die, &tmp);
 190                 if (ret)
 191                         return -ENOENT;
 192
 193                 if (probe_conf.show_location_range &&
 194                         (dwarf_tag(vr_die) == DW_TAG_variable)) {
 195                         ret2 = -ERANGE;
 196                 } else if (addr != tmp ||
 197                         dwarf_tag(vr_die) != DW_TAG_formal_parameter) {
 198                         return -ENOENT;
 199                 }
 200
 201                 ret = dwarf_highpc(sp_die, &tmp);
 202                 if (ret)
 203                         return -ENOENT;
 204                 /*
 205                  * This is fuzzed by fentry mcount. We try to find the
 206                  * parameter location at the earliest address.
 207                  */
 208                 for (addr += 1; addr <= tmp; addr++) {
 209                         if (dwarf_getlocation_addr(&attr, addr, &op,
 210                                                    &nops, 1) > 0)
 211                                 goto found;
 212                 }
 213                 return -ENOENT;
 214         }
 215 found:
 216         if (nops == 0)
 217                 /* TODO: Support const_value */
 218                 return -ENOENT;
 219
 220         if (op->atom == DW_OP_addr) {
 221 static_var:
 222                 if (!tvar)
 223                         return ret2;
 224                 /* Static variables on memory (not stack), make @varname */
 225                 ret = strlen(dwarf_diename(vr_die));
 226                 tvar->value = zalloc(ret + 2);
 227                 if (tvar->value == NULL)
 228                         return -ENOMEM;
 229                 snprintf(tvar->value, ret + 2, "@%s", dwarf_diename(vr_die));
 230                 tvar->ref = alloc_trace_arg_ref((long)offs);
 231                 if (tvar->ref == NULL)
 232                         return -ENOMEM;
 233                 return ret2;
 234         }
 235
 236         /* If this is based on frame buffer, set the offset */
 237         if (op->atom == DW_OP_fbreg) {
 238                 if (fb_ops == NULL)
 239                         return -ENOTSUP;
 240                 ref = true;
 241                 offs = op->number;
 242                 op = &fb_ops[0];
 243         }
 244
 245         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
 246                 regn = op->atom - DW_OP_breg0;
 247                 offs += op->number;
 248                 ref = true;
 249         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
 250                 regn = op->atom - DW_OP_reg0;
 251         } else if (op->atom == DW_OP_bregx) {
 252                 regn = op->number;
 253                 offs += op->number2;
 254                 ref = true;
 255         } else if (op->atom == DW_OP_regx) {
 256                 regn = op->number;
 257         } else {
 258                 pr_debug("DW_OP %x is not supported.\n", op->atom);
 259                 return -ENOTSUP;
 260         }
 261
 262         if (!tvar)
 263                 return ret2;
 264
 265         regs = get_arch_regstr(regn);
 266         if (!regs) {
 267                 /* This should be a bug in DWARF or this tool */
 268                 pr_warning("Mapping for the register number %u "
 269                            "missing on this architecture.\n", regn);
 270                 return -ENOTSUP;
 271         }
 272
 273         tvar->value = strdup(regs);
 274         if (tvar->value == NULL)
 275                 return -ENOMEM;
 276
 277         if (ref) {
 278                 tvar->ref = alloc_trace_arg_ref((long)offs);
 279                 if (tvar->ref == NULL)
 280                         return -ENOMEM;
 281         }
 282         return ret2;
 283 }
 284
 285 #define BYTES_TO_BITS(nb)       ((nb) * BITS_PER_LONG / sizeof(long))
 286
 287 static int convert_variable_type(Dwarf_Die *vr_die,
 288                                  struct probe_trace_arg *tvar,
 289                                  const char *cast)
 290 {
 291         struct probe_trace_arg_ref **ref_ptr = &tvar->ref;
 292         Dwarf_Die type;
 293         char buf[16];
 294         char sbuf[STRERR_BUFSIZE];
 295         int bsize, boffs, total;
 296         int ret;
 297
 298         /* TODO: check all types */
 299         if (cast && strcmp(cast, "string") != 0) {
 300                 /* Non string type is OK */
 301                 tvar->type = strdup(cast);
 302                 return (tvar->type == NULL) ? -ENOMEM : 0;
 303         }
 304
 305         bsize = dwarf_bitsize(vr_die);
 306         if (bsize > 0) {
 307                 /* This is a bitfield */
 308                 boffs = dwarf_bitoffset(vr_die);
 309                 total = dwarf_bytesize(vr_die);
 310                 if (boffs < 0 || total < 0)
 311                         return -ENOENT;
 312                 ret = snprintf(buf, 16, "b%d@%d/%zd", bsize, boffs,
 313                                 BYTES_TO_BITS(total));
 314                 goto formatted;
 315         }
 316
 317         if (die_get_real_type(vr_die, &type) == NULL) {
 318                 pr_warning("Failed to get a type information of %s.\n",
 319                            dwarf_diename(vr_die));
 320                 return -ENOENT;
 321         }
 322
 323         pr_debug("%s type is %s.\n",
 324                  dwarf_diename(vr_die), dwarf_diename(&type));
 325
 326         if (cast && strcmp(cast, "string") == 0) {      /* String type */
 327                 ret = dwarf_tag(&type);
 328                 if (ret != DW_TAG_pointer_type &&
 329                     ret != DW_TAG_array_type) {
 330                         pr_warning("Failed to cast into string: "
 331                                    "%s(%s) is not a pointer nor array.\n",
 332                                    dwarf_diename(vr_die), dwarf_diename(&type));
 333                         return -EINVAL;
 334                 }
 335                 if (die_get_real_type(&type, &type) == NULL) {
 336                         pr_warning("Failed to get a type"
 337                                    " information.\n");
 338                         return -ENOENT;
 339                 }
 340                 if (ret == DW_TAG_pointer_type) {
 341                         while (*ref_ptr)
 342                                 ref_ptr = &(*ref_ptr)->next;
 343                         /* Add new reference with offset +0 */
 344                         *ref_ptr = zalloc(sizeof(struct probe_trace_arg_ref));
 345                         if (*ref_ptr == NULL) {
 346                                 pr_warning("Out of memory error\n");
 347                                 return -ENOMEM;
 348                         }
 349                 }
 350                 if (!die_compare_name(&type, "char") &&
 351                     !die_compare_name(&type, "unsigned char")) {
 352                         pr_warning("Failed to cast into string: "
 353                                    "%s is not (unsigned) char *.\n",
 354                                    dwarf_diename(vr_die));
 355                         return -EINVAL;
 356                 }
 357                 tvar->type = strdup(cast);
 358                 return (tvar->type == NULL) ? -ENOMEM : 0;
 359         }
 360
 361         ret = dwarf_bytesize(&type);
 362         if (ret <= 0)
 363                 /* No size ... try to use default type */
 364                 return 0;
 365         ret = BYTES_TO_BITS(ret);
 366
 367         /* Check the bitwidth */
 368         if (ret > MAX_BASIC_TYPE_BITS) {
 369                 pr_info("%s exceeds max-bitwidth. Cut down to %d bits.\n",
 370                         dwarf_diename(&type), MAX_BASIC_TYPE_BITS);
 371                 ret = MAX_BASIC_TYPE_BITS;
 372         }
 373         ret = snprintf(buf, 16, "%c%d",
 374                        die_is_signed_type(&type) ? 's' : 'u', ret);
 375
 376 formatted:
 377         if (ret < 0 || ret >= 16) {
 378                 if (ret >= 16)
 379                         ret = -E2BIG;
 380                 pr_warning("Failed to convert variable type: %s\n",
 381                            strerror_r(-ret, sbuf, sizeof(sbuf)));
 382                 return ret;
 383         }
 384         tvar->type = strdup(buf);
 385         if (tvar->type == NULL)
 386                 return -ENOMEM;
 387         return 0;
 388 }
 389
 390 static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname,
 391                                     struct perf_probe_arg_field *field,
 392                                     struct probe_trace_arg_ref **ref_ptr,
 393                                     Dwarf_Die *die_mem)
 394 {
 395         struct probe_trace_arg_ref *ref = *ref_ptr;
 396         Dwarf_Die type;
 397         Dwarf_Word offs;
 398         int ret, tag;
 399
 400         pr_debug("converting %s in %s\n", field->name, varname);
 401         if (die_get_real_type(vr_die, &type) == NULL) {
 402                 pr_warning("Failed to get the type of %s.\n", varname);
 403                 return -ENOENT;
 404         }
 405         pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type));
 406         tag = dwarf_tag(&type);
 407
 408         if (field->name[0] == '[' &&
 409             (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) {
 410                 if (field->next)
 411                         /* Save original type for next field */
 412                         memcpy(die_mem, &type, sizeof(*die_mem));
 413                 /* Get the type of this array */
 414                 if (die_get_real_type(&type, &type) == NULL) {
 415                         pr_warning("Failed to get the type of %s.\n", varname);
 416                         return -ENOENT;
 417                 }
 418                 pr_debug2("Array real type: (%x)\n",
 419                          (unsigned)dwarf_dieoffset(&type));
 420                 if (tag == DW_TAG_pointer_type) {
 421                         ref = zalloc(sizeof(struct probe_trace_arg_ref));
 422                         if (ref == NULL)
 423                                 return -ENOMEM;
 424                         if (*ref_ptr)
 425                                 (*ref_ptr)->next = ref;
 426                         else
 427                                 *ref_ptr = ref;
 428                 }
 429                 ref->offset += dwarf_bytesize(&type) * field->index;
 430                 if (!field->next)
 431                         /* Save vr_die for converting types */
 432                         memcpy(die_mem, vr_die, sizeof(*die_mem));
 433                 goto next;
 434         } else if (tag == DW_TAG_pointer_type) {
 435                 /* Check the pointer and dereference */
 436                 if (!field->ref) {
 437                         pr_err("Semantic error: %s must be referred by '->'\n",
 438                                field->name);
 439                         return -EINVAL;
 440                 }
 441                 /* Get the type pointed by this pointer */
 442                 if (die_get_real_type(&type, &type) == NULL) {
 443                         pr_warning("Failed to get the type of %s.\n", varname);
 444                         return -ENOENT;
 445                 }
 446                 /* Verify it is a data structure  */
 447                 tag = dwarf_tag(&type);
 448                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 449                         pr_warning("%s is not a data structure nor an union.\n",
 450                                    varname);
 451                         return -EINVAL;
 452                 }
 453
 454                 ref = zalloc(sizeof(struct probe_trace_arg_ref));
 455                 if (ref == NULL)
 456                         return -ENOMEM;
 457                 if (*ref_ptr)
 458                         (*ref_ptr)->next = ref;
 459                 else
 460                         *ref_ptr = ref;
 461         } else {
 462                 /* Verify it is a data structure  */
 463                 if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) {
 464                         pr_warning("%s is not a data structure nor an union.\n",
 465                                    varname);
 466                         return -EINVAL;
 467                 }
 468                 if (field->name[0] == '[') {
 469                         pr_err("Semantic error: %s is not a pointer"
 470                                " nor array.\n", varname);
 471                         return -EINVAL;
 472                 }
 473                 /* While prcessing unnamed field, we don't care about this */
 474                 if (field->ref && dwarf_diename(vr_die)) {
 475                         pr_err("Semantic error: %s must be referred by '.'\n",
 476                                field->name);
 477                         return -EINVAL;
 478                 }
 479                 if (!ref) {
 480                         pr_warning("Structure on a register is not "
 481                                    "supported yet.\n");
 482                         return -ENOTSUP;
 483                 }
 484         }
 485
 486         if (die_find_member(&type, field->name, die_mem) == NULL) {
 487                 pr_warning("%s(type:%s) has no member %s.\n", varname,
 488                            dwarf_diename(&type), field->name);
 489                 return -EINVAL;
 490         }
 491
 492         /* Get the offset of the field */
 493         if (tag == DW_TAG_union_type) {
 494                 offs = 0;
 495         } else {
 496                 ret = die_get_data_member_location(die_mem, &offs);
 497                 if (ret < 0) {
 498                         pr_warning("Failed to get the offset of %s.\n",
 499                                    field->name);
 500                         return ret;
 501                 }
 502         }
 503         ref->offset += (long)offs;
 504
 505         /* If this member is unnamed, we need to reuse this field */
 506         if (!dwarf_diename(die_mem))
 507                 return convert_variable_fields(die_mem, varname, field,
 508                                                 &ref, die_mem);
 509
 510 next:
 511         /* Converting next field */
 512         if (field->next)
 513                 return convert_variable_fields(die_mem, field->name,
 514                                         field->next, &ref, die_mem);
 515         else
 516                 return 0;
 517 }
 518
 519 /* Show a variables in kprobe event format */
 520 static int convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 521 {
 522         Dwarf_Die die_mem;
 523         int ret;
 524
 525         pr_debug("Converting variable %s into trace event.\n",
 526                  dwarf_diename(vr_die));
 527
 528         ret = convert_variable_location(vr_die, pf->addr, pf->fb_ops,
 529                                         &pf->sp_die, pf->tvar);
 530         if (ret == -ENOENT || ret == -EINVAL) {
 531                 pr_err("Failed to find the location of the '%s' variable at this address.\n"
 532                        " Perhaps it has been optimized out.\n"
 533                        " Use -V with the --range option to show '%s' location range.\n",
 534                        pf->pvar->var, pf->pvar->var);
 535         } else if (ret == -ENOTSUP)
 536                 pr_err("Sorry, we don't support this variable location yet.\n");
 537         else if (ret == 0 && pf->pvar->field) {
 538                 ret = convert_variable_fields(vr_die, pf->pvar->var,
 539                                               pf->pvar->field, &pf->tvar->ref,
 540                                               &die_mem);
 541                 vr_die = &die_mem;
 542         }
 543         if (ret == 0)
 544                 ret = convert_variable_type(vr_die, pf->tvar, pf->pvar->type);
 545         /* *expr will be cached in libdw. Don't free it. */
 546         return ret;
 547 }
 548
 549 /* Find a variable in a scope DIE */
 550 static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf)
 551 {
 552         Dwarf_Die vr_die;
 553         char buf[32], *ptr;
 554         int ret = 0;
 555
 556         if (!is_c_varname(pf->pvar->var)) {
 557                 /* Copy raw parameters */
 558                 pf->tvar->value = strdup(pf->pvar->var);
 559                 if (pf->tvar->value == NULL)
 560                         return -ENOMEM;
 561                 if (pf->pvar->type) {
 562                         pf->tvar->type = strdup(pf->pvar->type);
 563                         if (pf->tvar->type == NULL)
 564                                 return -ENOMEM;
 565                 }
 566                 if (pf->pvar->name) {
 567                         pf->tvar->name = strdup(pf->pvar->name);
 568                         if (pf->tvar->name == NULL)
 569                                 return -ENOMEM;
 570                 } else
 571                         pf->tvar->name = NULL;
 572                 return 0;
 573         }
 574
 575         if (pf->pvar->name)
 576                 pf->tvar->name = strdup(pf->pvar->name);
 577         else {
 578                 ret = synthesize_perf_probe_arg(pf->pvar, buf, 32);
 579                 if (ret < 0)
 580                         return ret;
 581                 ptr = strchr(buf, ':'); /* Change type separator to _ */
 582                 if (ptr)
 583                         *ptr = '_';
 584                 pf->tvar->name = strdup(buf);
 585         }
 586         if (pf->tvar->name == NULL)
 587                 return -ENOMEM;
 588
 589         pr_debug("Searching '%s' variable in context.\n", pf->pvar->var);
 590         /* Search child die for local variables and parameters. */
 591         if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) {
 592                 /* Search again in global variables */
 593                 if (!die_find_variable_at(&pf->cu_die, pf->pvar->var,
 594                                                 0, &vr_die)) {
 595                         pr_warning("Failed to find '%s' in this function.\n",
 596                                    pf->pvar->var);
 597                         ret = -ENOENT;
 598                 }
 599         }
 600         if (ret >= 0)
 601                 ret = convert_variable(&vr_die, pf);
 602
 603         return ret;
 604 }
 605
 606 /* Convert subprogram DIE to trace point */
 607 static int convert_to_trace_point(Dwarf_Die *sp_die, Dwfl_Module *mod,
 608                                   Dwarf_Addr paddr, bool retprobe,
 609                                   struct probe_trace_point *tp)
 610 {
 611         Dwarf_Addr eaddr, highaddr;
 612         GElf_Sym sym;
 613         const char *symbol;
 614
 615         /* Verify the address is correct */
 616         if (dwarf_entrypc(sp_die, &eaddr) != 0) {
 617                 pr_warning("Failed to get entry address of %s\n",
 618                            dwarf_diename(sp_die));
 619                 return -ENOENT;
 620         }
 621         if (dwarf_highpc(sp_die, &highaddr) != 0) {
 622                 pr_warning("Failed to get end address of %s\n",
 623                            dwarf_diename(sp_die));
 624                 return -ENOENT;
 625         }
 626         if (paddr > highaddr) {
 627                 pr_warning("Offset specified is greater than size of %s\n",
 628                            dwarf_diename(sp_die));
 629                 return -EINVAL;
 630         }
 631
 632         symbol = dwarf_diename(sp_die);
 633         if (!symbol) {
 634                 /* Try to get the symbol name from symtab */
 635                 symbol = dwfl_module_addrsym(mod, paddr, &sym, NULL);
 636                 if (!symbol) {
 637                         pr_warning("Failed to find symbol at 0x%lx\n",
 638                                    (unsigned long)paddr);
 639                         return -ENOENT;
 640                 }
 641                 eaddr = sym.st_value;
 642         }
 643         tp->offset = (unsigned long)(paddr - eaddr);
 644         tp->address = (unsigned long)paddr;
 645         tp->symbol = strdup(symbol);
 646         if (!tp->symbol)
 647                 return -ENOMEM;
 648
 649         /* Return probe must be on the head of a subprogram */
 650         if (retprobe) {
 651                 if (eaddr != paddr) {
 652                         pr_warning("Return probe must be on the head of"
 653                                    " a real function.\n");
 654                         return -EINVAL;
 655                 }
 656                 tp->retprobe = true;
 657         }
 658
 659         return 0;
 660 }
 661
 662 /* Call probe_finder callback with scope DIE */
 663 static int call_probe_finder(Dwarf_Die *sc_die, struct probe_finder *pf)
 664 {
 665         Dwarf_Attribute fb_attr;
 666         size_t nops;
 667         int ret;
 668
 669         if (!sc_die) {
 670                 pr_err("Caller must pass a scope DIE. Program error.\n");
 671                 return -EINVAL;
 672         }
 673
 674         /* If not a real subprogram, find a real one */
 675         if (!die_is_func_def(sc_die)) {
 676                 if (!die_find_realfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 677                         if (die_find_tailfunc(&pf->cu_die, pf->addr, &pf->sp_die)) {
 678                                 pr_warning("Ignoring tail call from %s\n",
 679                                                 dwarf_diename(&pf->sp_die));
 680                                 return 0;
 681                         } else {
 682                                 pr_warning("Failed to find probe point in any "
 683                                            "functions.\n");
 684                                 return -ENOENT;
 685                         }
 686                 }
 687         } else
 688                 memcpy(&pf->sp_die, sc_die, sizeof(Dwarf_Die));
 689
 690         /* Get the frame base attribute/ops from subprogram */
 691         dwarf_attr(&pf->sp_die, DW_AT_frame_base, &fb_attr);
 692         ret = dwarf_getlocation_addr(&fb_attr, pf->addr, &pf->fb_ops, &nops, 1);
 693         if (ret <= 0 || nops == 0) {
 694                 pf->fb_ops = NULL;
 695 #if _ELFUTILS_PREREQ(0, 142)
 696         } else if (nops == 1 && pf->fb_ops[0].atom == DW_OP_call_frame_cfa &&
 697                    pf->cfi != NULL) {
 698                 Dwarf_Frame *frame;
 699                 if (dwarf_cfi_addrframe(pf->cfi, pf->addr, &frame) != 0 ||
 700                     dwarf_frame_cfa(frame, &pf->fb_ops, &nops) != 0) {
 701                         pr_warning("Failed to get call frame on 0x%jx\n",
 702                                    (uintmax_t)pf->addr);
 703                         return -ENOENT;
 704                 }
 705 #endif
 706         }
 707
 708         /* Call finder's callback handler */
 709         ret = pf->callback(sc_die, pf);
 710
 711         /* *pf->fb_ops will be cached in libdw. Don't free it. */
 712         pf->fb_ops = NULL;
 713
 714         return ret;
 715 }
 716
 717 struct find_scope_param {
 718         const char *function;
 719         const char *file;
 720         int line;
 721         int diff;
 722         Dwarf_Die *die_mem;
 723         bool found;
 724 };
 725
 726 static int find_best_scope_cb(Dwarf_Die *fn_die, void *data)
 727 {
 728         struct find_scope_param *fsp = data;
 729         const char *file;
 730         int lno;
 731
 732         /* Skip if declared file name does not match */
 733         if (fsp->file) {
 734                 file = dwarf_decl_file(fn_die);
 735                 if (!file || strcmp(fsp->file, file) != 0)
 736                         return 0;
 737         }
 738         /* If the function name is given, that's what user expects */
 739         if (fsp->function) {
 740                 if (die_match_name(fn_die, fsp->function)) {
 741                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 742                         fsp->found = true;
 743                         return 1;
 744                 }
 745         } else {
 746                 /* With the line number, find the nearest declared DIE */
 747                 dwarf_decl_line(fn_die, &lno);
 748                 if (lno < fsp->line && fsp->diff > fsp->line - lno) {
 749                         /* Keep a candidate and continue */
 750                         fsp->diff = fsp->line - lno;
 751                         memcpy(fsp->die_mem, fn_die, sizeof(Dwarf_Die));
 752                         fsp->found = true;
 753                 }
 754         }
 755         return 0;
 756 }
 757
 758 /* Find an appropriate scope fits to given conditions */
 759 static Dwarf_Die *find_best_scope(struct probe_finder *pf, Dwarf_Die *die_mem)
 760 {
 761         struct find_scope_param fsp = {
 762                 .function = pf->pev->point.function,
 763                 .file = pf->fname,
 764                 .line = pf->lno,
 765                 .diff = INT_MAX,
 766                 .die_mem = die_mem,
 767                 .found = false,
 768         };
 769
 770         cu_walk_functions_at(&pf->cu_die, pf->addr, find_best_scope_cb, &fsp);
 771
 772         return fsp.found ? die_mem : NULL;
 773 }
 774
 775 static int probe_point_line_walker(const char *fname, int lineno,
 776                                    Dwarf_Addr addr, void *data)
 777 {
 778         struct probe_finder *pf = data;
 779         Dwarf_Die *sc_die, die_mem;
 780         int ret;
 781
 782         if (lineno != pf->lno || strtailcmp(fname, pf->fname) != 0)
 783                 return 0;
 784
 785         pf->addr = addr;
 786         sc_die = find_best_scope(pf, &die_mem);
 787         if (!sc_die) {
 788                 pr_warning("Failed to find scope of probe point.\n");
 789                 return -ENOENT;
 790         }
 791
 792         ret = call_probe_finder(sc_die, pf);
 793
 794         /* Continue if no error, because the line will be in inline function */
 795         return ret < 0 ? ret : 0;
 796 }
 797
 798 /* Find probe point from its line number */
 799 static int find_probe_point_by_line(struct probe_finder *pf)
 800 {
 801         return die_walk_lines(&pf->cu_die, probe_point_line_walker, pf);
 802 }
 803
 804 /* Find lines which match lazy pattern */
 805 static int find_lazy_match_lines(struct intlist *list,
 806                                  const char *fname, const char *pat)
 807 {
 808         FILE *fp;
 809         char *line = NULL;
 810         size_t line_len;
 811         ssize_t len;
 812         int count = 0, linenum = 1;
 813         char sbuf[STRERR_BUFSIZE];
 814
 815         fp = fopen(fname, "r");
 816         if (!fp) {
 817                 pr_warning("Failed to open %s: %s\n", fname,
 818                            strerror_r(errno, sbuf, sizeof(sbuf)));
 819                 return -errno;
 820         }
 821
 822         while ((len = getline(&line, &line_len, fp)) > 0) {
 823
 824                 if (line[len - 1] == '\n')
 825                         line[len - 1] = '\0';
 826
 827                 if (strlazymatch(line, pat)) {
 828                         intlist__add(list, linenum);
 829                         count++;
 830                 }
 831                 linenum++;
 832         }
 833
 834         if (ferror(fp))
 835                 count = -errno;
 836         free(line);
 837         fclose(fp);
 838
 839         if (count == 0)
 840                 pr_debug("No matched lines found in %s.\n", fname);
 841         return count;
 842 }
 843
 844 static int probe_point_lazy_walker(const char *fname, int lineno,
 845                                    Dwarf_Addr addr, void *data)
 846 {
 847         struct probe_finder *pf = data;
 848         Dwarf_Die *sc_die, die_mem;
 849         int ret;
 850
 851         if (!intlist__has_entry(pf->lcache, lineno) ||
 852             strtailcmp(fname, pf->fname) != 0)
 853                 return 0;
 854
 855         pr_debug("Probe line found: line:%d addr:0x%llx\n",
 856                  lineno, (unsigned long long)addr);
 857         pf->addr = addr;
 858         pf->lno = lineno;
 859         sc_die = find_best_scope(pf, &die_mem);
 860         if (!sc_die) {
 861                 pr_warning("Failed to find scope of probe point.\n");
 862                 return -ENOENT;
 863         }
 864
 865         ret = call_probe_finder(sc_die, pf);
 866
 867         /*
 868          * Continue if no error, because the lazy pattern will match
 869          * to other lines
 870          */
 871         return ret < 0 ? ret : 0;
 872 }
 873
 874 /* Find probe points from lazy pattern  */
 875 static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 876 {
 877         int ret = 0;
 878         char *fpath;
 879
 880         if (intlist__empty(pf->lcache)) {
 881                 const char *comp_dir;
 882
 883                 comp_dir = cu_get_comp_dir(&pf->cu_die);
 884                 ret = get_real_path(pf->fname, comp_dir, &fpath);
 885                 if (ret < 0) {
 886                         pr_warning("Failed to find source file path.\n");
 887                         return ret;
 888                 }
 889
 890                 /* Matching lazy line pattern */
 891                 ret = find_lazy_match_lines(pf->lcache, fpath,
 892                                             pf->pev->point.lazy_line);
 893                 free(fpath);
 894                 if (ret <= 0)
 895                         return ret;
 896         }
 897
 898         return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
 899 }
 900
 901 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 902 {
 903         struct probe_finder *pf = data;
 904         struct perf_probe_point *pp = &pf->pev->point;
 905         Dwarf_Addr addr;
 906         int ret;
 907
 908         if (pp->lazy_line)
 909                 ret = find_probe_point_lazy(in_die, pf);
 910         else {
 911                 /* Get probe address */
 912                 if (dwarf_entrypc(in_die, &addr) != 0) {
 913                         pr_warning("Failed to get entry address of %s.\n",
 914                                    dwarf_diename(in_die));
 915                         return -ENOENT;
 916                 }
 917                 pf->addr = addr;
 918                 pf->addr += pp->offset;
 919                 pr_debug("found inline addr: 0x%jx\n",
 920                          (uintmax_t)pf->addr);
 921
 922                 ret = call_probe_finder(in_die, pf);
 923         }
 924
 925         return ret;
 926 }
 927
 928 /* Callback parameter with return value for libdw */
 929 struct dwarf_callback_param {
 930         void *data;
 931         int retval;
 932 };
 933
 934 /* Search function from function name */
 935 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 936 {
 937         struct dwarf_callback_param *param = data;
 938         struct probe_finder *pf = param->data;
 939         struct perf_probe_point *pp = &pf->pev->point;
 940
 941         /* Check tag and diename */
 942         if (!die_is_func_def(sp_die) ||
 943             !die_match_name(sp_die, pp->function))
 944                 return DWARF_CB_OK;
 945
 946         /* Check declared file */
 947         if (pp->file && strtailcmp(pp->file, dwarf_decl_file(sp_die)))
 948                 return DWARF_CB_OK;
 949
 950         pr_debug("Matched function: %s\n", dwarf_diename(sp_die));
 951         pf->fname = dwarf_decl_file(sp_die);
 952         if (pp->line) { /* Function relative line */
 953                 dwarf_decl_line(sp_die, &pf->lno);
 954                 pf->lno += pp->line;
 955                 param->retval = find_probe_point_by_line(pf);
 956         } else if (die_is_func_instance(sp_die)) {
 957                 /* Instances always have the entry address */
 958                 dwarf_entrypc(sp_die, &pf->addr);
 959                 /* Real function */
 960                 if (pp->lazy_line)
 961                         param->retval = find_probe_point_lazy(sp_die, pf);
 962                 else {
 963                         pf->addr += pp->offset;
 964                         /* TODO: Check the address in this function */
 965                         param->retval = call_probe_finder(sp_die, pf);
 966                 }
 967         } else if (!probe_conf.no_inlines) {
 968                 /* Inlined function: search instances */
 969                 param->retval = die_walk_instances(sp_die,
 970                                         probe_point_inline_cb, (void *)pf);
 971                 /* This could be a non-existed inline definition */
 972                 if (param->retval == -ENOENT && strisglob(pp->function))
 973                         param->retval = 0;
 974         }
 975
 976         /* We need to find other candidates */
 977         if (strisglob(pp->function) && param->retval >= 0) {
 978                 param->retval = 0;      /* We have to clear the result */
 979                 return DWARF_CB_OK;
 980         }
 981
 982         return DWARF_CB_ABORT; /* Exit; no same symbol in this CU. */
 983 }
 984
 985 static int find_probe_point_by_func(struct probe_finder *pf)
 986 {
 987         struct dwarf_callback_param _param = {.data = (void *)pf,
 988                                               .retval = 0};
 989         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, &_param, 0);
 990         return _param.retval;
 991 }
 992
 993 struct pubname_callback_param {
 994         char *function;
 995         char *file;
 996         Dwarf_Die *cu_die;
 997         Dwarf_Die *sp_die;
 998         int found;
 999 };
1000
1001 static int pubname_search_cb(Dwarf *dbg, Dwarf_Global *gl, void *data)
1002 {
1003         struct pubname_callback_param *param = data;
1004
1005         if (dwarf_offdie(dbg, gl->die_offset, param->sp_die)) {
1006                 if (dwarf_tag(param->sp_die) != DW_TAG_subprogram)
1007                         return DWARF_CB_OK;
1008
1009                 if (die_match_name(param->sp_die, param->function)) {
1010                         if (!dwarf_offdie(dbg, gl->cu_offset, param->cu_die))
1011                                 return DWARF_CB_OK;
1012
1013                         if (param->file &&
1014                             strtailcmp(param->file, dwarf_decl_file(param->sp_die)))
1015                                 return DWARF_CB_OK;
1016
1017                         param->found = 1;
1018                         return DWARF_CB_ABORT;
1019                 }
1020         }
1021
1022         return DWARF_CB_OK;
1023 }
1024
1025 /* Find probe points from debuginfo */
1026 static int debuginfo__find_probes(struct debuginfo *dbg,
1027                                   struct probe_finder *pf)
1028 {
1029         struct perf_probe_point *pp = &pf->pev->point;
1030         Dwarf_Off off, noff;
1031         size_t cuhl;
1032         Dwarf_Die *diep;
1033         int ret = 0;
1034
1035 #if _ELFUTILS_PREREQ(0, 142)
1036         Elf *elf;
1037         GElf_Ehdr ehdr;
1038         GElf_Shdr shdr;
1039
1040         /* Get the call frame information from this dwarf */
1041         elf = dwarf_getelf(dbg->dbg);
1042         if (elf == NULL)
1043                 return -EINVAL;
1044
1045         if (gelf_getehdr(elf, &ehdr) == NULL)
1046                 return -EINVAL;
1047
1048         if (elf_section_by_name(elf, &ehdr, &shdr, ".eh_frame", NULL) &&
1049             shdr.sh_type == SHT_PROGBITS) {
1050                 pf->cfi = dwarf_getcfi_elf(elf);
1051         } else {
1052                 pf->cfi = dwarf_getcfi(dbg->dbg);
1053         }
1054 #endif
1055
1056         off = 0;
1057         pf->lcache = intlist__new(NULL);
1058         if (!pf->lcache)
1059                 return -ENOMEM;
1060
1061         /* Fastpath: lookup by function name from .debug_pubnames section */
1062         if (pp->function && !strisglob(pp->function)) {
1063                 struct pubname_callback_param pubname_param = {
1064                         .function = pp->function,
1065                         .file     = pp->file,
1066                         .cu_die   = &pf->cu_die,
1067                         .sp_die   = &pf->sp_die,
1068                         .found    = 0,
1069                 };
1070                 struct dwarf_callback_param probe_param = {
1071                         .data = pf,
1072                 };
1073
1074                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1075                                   &pubname_param, 0);
1076                 if (pubname_param.found) {
1077                         ret = probe_point_search_cb(&pf->sp_die, &probe_param);
1078                         if (ret)
1079                                 goto found;
1080                 }
1081         }
1082
1083         /* Loop on CUs (Compilation Unit) */
1084         while (!dwarf_nextcu(dbg->dbg, off, &noff, &cuhl, NULL, NULL, NULL)) {
1085                 /* Get the DIE(Debugging Information Entry) of this CU */
1086                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &pf->cu_die);
1087                 if (!diep)
1088                         continue;
1089
1090                 /* Check if target file is included. */
1091                 if (pp->file)
1092                         pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
1093                 else
1094                         pf->fname = NULL;
1095
1096                 if (!pp->file || pf->fname) {
1097                         if (pp->function)
1098                                 ret = find_probe_point_by_func(pf);
1099                         else if (pp->lazy_line)
1100                                 ret = find_probe_point_lazy(&pf->cu_die, pf);
1101                         else {
1102                                 pf->lno = pp->line;
1103                                 ret = find_probe_point_by_line(pf);
1104                         }
1105                         if (ret < 0)
1106                                 break;
1107                 }
1108                 off = noff;
1109         }
1110
1111 found:
1112         intlist__delete(pf->lcache);
1113         pf->lcache = NULL;
1114
1115         return ret;
1116 }
1117
1118 struct local_vars_finder {
1119         struct probe_finder *pf;
1120         struct perf_probe_arg *args;
1121         bool vars;
1122         int max_args;
1123         int nargs;
1124         int ret;
1125 };
1126
1127 /* Collect available variables in this scope */
1128 static int copy_variables_cb(Dwarf_Die *die_mem, void *data)
1129 {
1130         struct local_vars_finder *vf = data;
1131         struct probe_finder *pf = vf->pf;
1132         int tag;
1133
1134         tag = dwarf_tag(die_mem);
1135         if (tag == DW_TAG_formal_parameter ||
1136             (tag == DW_TAG_variable && vf->vars)) {
1137                 if (convert_variable_location(die_mem, vf->pf->addr,
1138                                               vf->pf->fb_ops, &pf->sp_die,
1139                                               NULL) == 0) {
1140                         vf->args[vf->nargs].var = (char *)dwarf_diename(die_mem);
1141                         if (vf->args[vf->nargs].var == NULL) {
1142                                 vf->ret = -ENOMEM;
1143                                 return DIE_FIND_CB_END;
1144                         }
1145                         pr_debug(" %s", vf->args[vf->nargs].var);
1146                         vf->nargs++;
1147                 }
1148         }
1149
1150         if (dwarf_haspc(die_mem, vf->pf->addr))
1151                 return DIE_FIND_CB_CONTINUE;
1152         else
1153                 return DIE_FIND_CB_SIBLING;
1154 }
1155
1156 static int expand_probe_args(Dwarf_Die *sc_die, struct probe_finder *pf,
1157                              struct perf_probe_arg *args)
1158 {
1159         Dwarf_Die die_mem;
1160         int i;
1161         int n = 0;
1162         struct local_vars_finder vf = {.pf = pf, .args = args, .vars = false,
1163                                 .max_args = MAX_PROBE_ARGS, .ret = 0};
1164
1165         for (i = 0; i < pf->pev->nargs; i++) {
1166                 /* var never be NULL */
1167                 if (strcmp(pf->pev->args[i].var, PROBE_ARG_VARS) == 0)
1168                         vf.vars = true;
1169                 else if (strcmp(pf->pev->args[i].var, PROBE_ARG_PARAMS) != 0) {
1170                         /* Copy normal argument */
1171                         args[n] = pf->pev->args[i];
1172                         n++;
1173                         continue;
1174                 }
1175                 pr_debug("Expanding %s into:", pf->pev->args[i].var);
1176                 vf.nargs = n;
1177                 /* Special local variables */
1178                 die_find_child(sc_die, copy_variables_cb, (void *)&vf,
1179                                &die_mem);
1180                 pr_debug(" (%d)\n", vf.nargs - n);
1181                 if (vf.ret < 0)
1182                         return vf.ret;
1183                 n = vf.nargs;
1184         }
1185         return n;
1186 }
1187
1188 /* Add a found probe point into trace event list */
1189 static int add_probe_trace_event(Dwarf_Die *sc_die, struct probe_finder *pf)
1190 {
1191         struct trace_event_finder *tf =
1192                         container_of(pf, struct trace_event_finder, pf);
1193         struct probe_trace_event *tev;
1194         struct perf_probe_arg *args;
1195         int ret, i;
1196
1197         /* Check number of tevs */
1198         if (tf->ntevs == tf->max_tevs) {
1199                 pr_warning("Too many( > %d) probe point found.\n",
1200                            tf->max_tevs);
1201                 return -ERANGE;
1202         }
1203         tev = &tf->tevs[tf->ntevs++];
1204
1205         /* Trace point should be converted from subprogram DIE */
1206         ret = convert_to_trace_point(&pf->sp_die, tf->mod, pf->addr,
1207                                      pf->pev->point.retprobe, &tev->point);
1208         if (ret < 0)
1209                 return ret;
1210
1211         tev->point.realname = strdup(dwarf_diename(sc_die));
1212         if (!tev->point.realname)
1213                 return -ENOMEM;
1214
1215         pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
1216                  tev->point.offset);
1217
1218         /* Expand special probe argument if exist */
1219         args = zalloc(sizeof(struct perf_probe_arg) * MAX_PROBE_ARGS);
1220         if (args == NULL)
1221                 return -ENOMEM;
1222
1223         ret = expand_probe_args(sc_die, pf, args);
1224         if (ret < 0)
1225                 goto end;
1226
1227         tev->nargs = ret;
1228         tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
1229         if (tev->args == NULL) {
1230                 ret = -ENOMEM;
1231                 goto end;
1232         }
1233
1234         /* Find each argument */
1235         for (i = 0; i < tev->nargs; i++) {
1236                 pf->pvar = &args[i];
1237                 pf->tvar = &tev->args[i];
1238                 /* Variable should be found from scope DIE */
1239                 ret = find_variable(sc_die, pf);
1240                 if (ret != 0)
1241                         break;
1242         }
1243
1244 end:
1245         free(args);
1246         return ret;
1247 }
1248
1249 /* Find probe_trace_events specified by perf_probe_event from debuginfo */
1250 int debuginfo__find_trace_events(struct debuginfo *dbg,
1251                                  struct perf_probe_event *pev,
1252                                  struct probe_trace_event **tevs)
1253 {
1254         struct trace_event_finder tf = {
1255                         .pf = {.pev = pev, .callback = add_probe_trace_event},
1256                         .max_tevs = probe_conf.max_probes, .mod = dbg->mod};
1257         int ret;
1258
1259         /* Allocate result tevs array */
1260         *tevs = zalloc(sizeof(struct probe_trace_event) * tf.max_tevs);
1261         if (*tevs == NULL)
1262                 return -ENOMEM;
1263
1264         tf.tevs = *tevs;
1265         tf.ntevs = 0;
1266
1267         ret = debuginfo__find_probes(dbg, &tf.pf);
1268         if (ret < 0) {
1269                 zfree(tevs);
1270                 return ret;
1271         }
1272
1273         return (ret < 0) ? ret : tf.ntevs;
1274 }
1275
1276 /* Collect available variables in this scope */
1277 static int collect_variables_cb(Dwarf_Die *die_mem, void *data)
1278 {
1279         struct available_var_finder *af = data;
1280         struct variable_list *vl;
1281         int tag, ret;
1282
1283         vl = &af->vls[af->nvls - 1];
1284
1285         tag = dwarf_tag(die_mem);
1286         if (tag == DW_TAG_formal_parameter ||
1287             tag == DW_TAG_variable) {
1288                 ret = convert_variable_location(die_mem, af->pf.addr,
1289                                                 af->pf.fb_ops, &af->pf.sp_die,
1290                                                 NULL);
1291                 if (ret == 0 || ret == -ERANGE) {
1292                         int ret2;
1293                         bool externs = !af->child;
1294                         struct strbuf buf;
1295
1296                         strbuf_init(&buf, 64);
1297
1298                         if (probe_conf.show_location_range) {
1299                                 if (!externs) {
1300                                         if (ret)
1301                                                 strbuf_addf(&buf, "[INV]\t");
1302                                         else
1303                                                 strbuf_addf(&buf, "[VAL]\t");
1304                                 } else
1305                                         strbuf_addf(&buf, "[EXT]\t");
1306                         }
1307
1308                         ret2 = die_get_varname(die_mem, &buf);
1309
1310                         if (!ret2 && probe_conf.show_location_range &&
1311                                 !externs) {
1312                                 strbuf_addf(&buf, "\t");
1313                                 ret2 = die_get_var_range(&af->pf.sp_die,
1314                                                         die_mem, &buf);
1315                         }
1316
1317                         pr_debug("Add new var: %s\n", buf.buf);
1318                         if (ret2 == 0) {
1319                                 strlist__add(vl->vars,
1320                                         strbuf_detach(&buf, NULL));
1321                         }
1322                         strbuf_release(&buf);
1323                 }
1324         }
1325
1326         if (af->child && dwarf_haspc(die_mem, af->pf.addr))
1327                 return DIE_FIND_CB_CONTINUE;
1328         else
1329                 return DIE_FIND_CB_SIBLING;
1330 }
1331
1332 /* Add a found vars into available variables list */
1333 static int add_available_vars(Dwarf_Die *sc_die, struct probe_finder *pf)
1334 {
1335         struct available_var_finder *af =
1336                         container_of(pf, struct available_var_finder, pf);
1337         struct variable_list *vl;
1338         Dwarf_Die die_mem;
1339         int ret;
1340
1341         /* Check number of tevs */
1342         if (af->nvls == af->max_vls) {
1343                 pr_warning("Too many( > %d) probe point found.\n", af->max_vls);
1344                 return -ERANGE;
1345         }
1346         vl = &af->vls[af->nvls++];
1347
1348         /* Trace point should be converted from subprogram DIE */
1349         ret = convert_to_trace_point(&pf->sp_die, af->mod, pf->addr,
1350                                      pf->pev->point.retprobe, &vl->point);
1351         if (ret < 0)
1352                 return ret;
1353
1354         pr_debug("Probe point found: %s+%lu\n", vl->point.symbol,
1355                  vl->point.offset);
1356
1357         /* Find local variables */
1358         vl->vars = strlist__new(true, NULL);
1359         if (vl->vars == NULL)
1360                 return -ENOMEM;
1361         af->child = true;
1362         die_find_child(sc_die, collect_variables_cb, (void *)af, &die_mem);
1363
1364         /* Find external variables */
1365         if (!probe_conf.show_ext_vars)
1366                 goto out;
1367         /* Don't need to search child DIE for external vars. */
1368         af->child = false;
1369         die_find_child(&pf->cu_die, collect_variables_cb, (void *)af, &die_mem);
1370
1371 out:
1372         if (strlist__empty(vl->vars)) {
1373                 strlist__delete(vl->vars);
1374                 vl->vars = NULL;
1375         }
1376
1377         return ret;
1378 }
1379
1380 /*
1381  * Find available variables at given probe point
1382  * Return the number of found probe points. Return 0 if there is no
1383  * matched probe point. Return <0 if an error occurs.
1384  */
1385 int debuginfo__find_available_vars_at(struct debuginfo *dbg,
1386                                       struct perf_probe_event *pev,
1387                                       struct variable_list **vls)
1388 {
1389         struct available_var_finder af = {
1390                         .pf = {.pev = pev, .callback = add_available_vars},
1391                         .mod = dbg->mod,
1392                         .max_vls = probe_conf.max_probes};
1393         int ret;
1394
1395         /* Allocate result vls array */
1396         *vls = zalloc(sizeof(struct variable_list) * af.max_vls);
1397         if (*vls == NULL)
1398                 return -ENOMEM;
1399
1400         af.vls = *vls;
1401         af.nvls = 0;
1402
1403         ret = debuginfo__find_probes(dbg, &af.pf);
1404         if (ret < 0) {
1405                 /* Free vlist for error */
1406                 while (af.nvls--) {
1407                         zfree(&af.vls[af.nvls].point.symbol);
1408                         strlist__delete(af.vls[af.nvls].vars);
1409                 }
1410                 zfree(vls);
1411                 return ret;
1412         }
1413
1414         return (ret < 0) ? ret : af.nvls;
1415 }
1416
1417 /* Reverse search */
1418 int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
1419                                 struct perf_probe_point *ppt)
1420 {
1421         Dwarf_Die cudie, spdie, indie;
1422         Dwarf_Addr _addr = 0, baseaddr = 0;
1423         const char *fname = NULL, *func = NULL, *basefunc = NULL, *tmp;
1424         int baseline = 0, lineno = 0, ret = 0;
1425
1426         /* Find cu die */
1427         if (!dwarf_addrdie(dbg->dbg, (Dwarf_Addr)addr, &cudie)) {
1428                 pr_warning("Failed to find debug information for address %lx\n",
1429                            addr);
1430                 ret = -EINVAL;
1431                 goto end;
1432         }
1433
1434         /* Find a corresponding line (filename and lineno) */
1435         cu_find_lineinfo(&cudie, addr, &fname, &lineno);
1436         /* Don't care whether it failed or not */
1437
1438         /* Find a corresponding function (name, baseline and baseaddr) */
1439         if (die_find_realfunc(&cudie, (Dwarf_Addr)addr, &spdie)) {
1440                 /* Get function entry information */
1441                 func = basefunc = dwarf_diename(&spdie);
1442                 if (!func ||
1443                     dwarf_entrypc(&spdie, &baseaddr) != 0 ||
1444                     dwarf_decl_line(&spdie, &baseline) != 0) {
1445                         lineno = 0;
1446                         goto post;
1447                 }
1448
1449                 fname = dwarf_decl_file(&spdie);
1450                 if (addr == (unsigned long)baseaddr) {
1451                         /* Function entry - Relative line number is 0 */
1452                         lineno = baseline;
1453                         goto post;
1454                 }
1455
1456                 /* Track down the inline functions step by step */
1457                 while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
1458                                                 &indie)) {
1459                         /* There is an inline function */
1460                         if (dwarf_entrypc(&indie, &_addr) == 0 &&
1461                             _addr == addr) {
1462                                 /*
1463                                  * addr is at an inline function entry.
1464                                  * In this case, lineno should be the call-site
1465                                  * line number. (overwrite lineinfo)
1466                                  */
1467                                 lineno = die_get_call_lineno(&indie);
1468                                 fname = die_get_call_file(&indie);
1469                                 break;
1470                         } else {
1471                                 /*
1472                                  * addr is in an inline function body.
1473                                  * Since lineno points one of the lines
1474                                  * of the inline function, baseline should
1475                                  * be the entry line of the inline function.
1476                                  */
1477                                 tmp = dwarf_diename(&indie);
1478                                 if (!tmp ||
1479                                     dwarf_decl_line(&indie, &baseline) != 0)
1480                                         break;
1481                                 func = tmp;
1482                                 spdie = indie;
1483                         }
1484                 }
1485                 /* Verify the lineno and baseline are in a same file */
1486                 tmp = dwarf_decl_file(&spdie);
1487                 if (!tmp || strcmp(tmp, fname) != 0)
1488                         lineno = 0;
1489         }
1490
1491 post:
1492         /* Make a relative line number or an offset */
1493         if (lineno)
1494                 ppt->line = lineno - baseline;
1495         else if (basefunc) {
1496                 ppt->offset = addr - (unsigned long)baseaddr;
1497                 func = basefunc;
1498         }
1499
1500         /* Duplicate strings */
1501         if (func) {
1502                 ppt->function = strdup(func);
1503                 if (ppt->function == NULL) {
1504                         ret = -ENOMEM;
1505                         goto end;
1506                 }
1507         }
1508         if (fname) {
1509                 ppt->file = strdup(fname);
1510                 if (ppt->file == NULL) {
1511                         zfree(&ppt->function);
1512                         ret = -ENOMEM;
1513                         goto end;
1514                 }
1515         }
1516 end:
1517         if (ret == 0 && (fname || func))
1518                 ret = 1;        /* Found a point */
1519         return ret;
1520 }
1521
1522 /* Add a line and store the src path */
1523 static int line_range_add_line(const char *src, unsigned int lineno,
1524                                struct line_range *lr)
1525 {
1526         /* Copy source path */
1527         if (!lr->path) {
1528                 lr->path = strdup(src);
1529                 if (lr->path == NULL)
1530                         return -ENOMEM;
1531         }
1532         return intlist__add(lr->line_list, lineno);
1533 }
1534
1535 static int line_range_walk_cb(const char *fname, int lineno,
1536                               Dwarf_Addr addr __maybe_unused,
1537                               void *data)
1538 {
1539         struct line_finder *lf = data;
1540         int err;
1541
1542         if ((strtailcmp(fname, lf->fname) != 0) ||
1543             (lf->lno_s > lineno || lf->lno_e < lineno))
1544                 return 0;
1545
1546         err = line_range_add_line(fname, lineno, lf->lr);
1547         if (err < 0 && err != -EEXIST)
1548                 return err;
1549
1550         return 0;
1551 }
1552
1553 /* Find line range from its line number */
1554 static int find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
1555 {
1556         int ret;
1557
1558         ret = die_walk_lines(sp_die ?: &lf->cu_die, line_range_walk_cb, lf);
1559
1560         /* Update status */
1561         if (ret >= 0)
1562                 if (!intlist__empty(lf->lr->line_list))
1563                         ret = lf->found = 1;
1564                 else
1565                         ret = 0;        /* Lines are not found */
1566         else {
1567                 zfree(&lf->lr->path);
1568         }
1569         return ret;
1570 }
1571
1572 static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
1573 {
1574         int ret = find_line_range_by_line(in_die, data);
1575
1576         /*
1577          * We have to check all instances of inlined function, because
1578          * some execution paths can be optimized out depends on the
1579          * function argument of instances. However, if an error occurs,
1580          * it should be handled by the caller.
1581          */
1582         return ret < 0 ? ret : 0;
1583 }
1584
1585 /* Search function definition from function name */
1586 static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
1587 {
1588         struct dwarf_callback_param *param = data;
1589         struct line_finder *lf = param->data;
1590         struct line_range *lr = lf->lr;
1591
1592         /* Check declared file */
1593         if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
1594                 return DWARF_CB_OK;
1595
1596         if (die_is_func_def(sp_die) &&
1597             die_match_name(sp_die, lr->function)) {
1598                 lf->fname = dwarf_decl_file(sp_die);
1599                 dwarf_decl_line(sp_die, &lr->offset);
1600                 pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
1601                 lf->lno_s = lr->offset + lr->start;
1602                 if (lf->lno_s < 0)      /* Overflow */
1603                         lf->lno_s = INT_MAX;
1604                 lf->lno_e = lr->offset + lr->end;
1605                 if (lf->lno_e < 0)      /* Overflow */
1606                         lf->lno_e = INT_MAX;
1607                 pr_debug("New line range: %d to %d\n", lf->lno_s, lf->lno_e);
1608                 lr->start = lf->lno_s;
1609                 lr->end = lf->lno_e;
1610                 if (!die_is_func_instance(sp_die))
1611                         param->retval = die_walk_instances(sp_die,
1612                                                 line_range_inline_cb, lf);
1613                 else
1614                         param->retval = find_line_range_by_line(sp_die, lf);
1615                 return DWARF_CB_ABORT;
1616         }
1617         return DWARF_CB_OK;
1618 }
1619
1620 static int find_line_range_by_func(struct line_finder *lf)
1621 {
1622         struct dwarf_callback_param param = {.data = (void *)lf, .retval = 0};
1623         dwarf_getfuncs(&lf->cu_die, line_range_search_cb, &param, 0);
1624         return param.retval;
1625 }
1626
1627 int debuginfo__find_line_range(struct debuginfo *dbg, struct line_range *lr)
1628 {
1629         struct line_finder lf = {.lr = lr, .found = 0};
1630         int ret = 0;
1631         Dwarf_Off off = 0, noff;
1632         size_t cuhl;
1633         Dwarf_Die *diep;
1634         const char *comp_dir;
1635
1636         /* Fastpath: lookup by function name from .debug_pubnames section */
1637         if (lr->function) {
1638                 struct pubname_callback_param pubname_param = {
1639                         .function = lr->function, .file = lr->file,
1640                         .cu_die = &lf.cu_die, .sp_die = &lf.sp_die, .found = 0};
1641                 struct dwarf_callback_param line_range_param = {
1642                         .data = (void *)&lf, .retval = 0};
1643
1644                 dwarf_getpubnames(dbg->dbg, pubname_search_cb,
1645                                   &pubname_param, 0);
1646                 if (pubname_param.found) {
1647                         line_range_search_cb(&lf.sp_die, &line_range_param);
1648                         if (lf.found)
1649                                 goto found;
1650                 }
1651         }
1652
1653         /* Loop on CUs (Compilation Unit) */
1654         while (!lf.found && ret >= 0) {
1655                 if (dwarf_nextcu(dbg->dbg, off, &noff, &cuhl,
1656                                  NULL, NULL, NULL) != 0)
1657                         break;
1658
1659                 /* Get the DIE(Debugging Information Entry) of this CU */
1660                 diep = dwarf_offdie(dbg->dbg, off + cuhl, &lf.cu_die);
1661                 if (!diep)
1662                         continue;
1663
1664                 /* Check if target file is included. */
1665                 if (lr->file)
1666                         lf.fname = cu_find_realpath(&lf.cu_die, lr->file);
1667                 else
1668                         lf.fname = 0;
1669
1670                 if (!lr->file || lf.fname) {
1671                         if (lr->function)
1672                                 ret = find_line_range_by_func(&lf);
1673                         else {
1674                                 lf.lno_s = lr->start;
1675                                 lf.lno_e = lr->end;
1676                                 ret = find_line_range_by_line(NULL, &lf);
1677                         }
1678                 }
1679                 off = noff;
1680         }
1681
1682 found:
1683         /* Store comp_dir */
1684         if (lf.found) {
1685                 comp_dir = cu_get_comp_dir(&lf.cu_die);
1686                 if (comp_dir) {
1687                         lr->comp_dir = strdup(comp_dir);
1688                         if (!lr->comp_dir)
1689                                 ret = -ENOMEM;
1690                 }
1691         }
1692
1693         pr_debug("path: %s\n", lr->path);
1694         return (ret < 0) ? ret : lf.found;
1695 }
1696
1697 /*
1698  * Find a src file from a DWARF tag path. Prepend optional source path prefix
1699  * and chop off leading directories that do not exist. Result is passed back as
1700  * a newly allocated path on success.
1701  * Return 0 if file was found and readable, -errno otherwise.
1702  */
1703 int get_real_path(const char *raw_path, const char *comp_dir,
1704                          char **new_path)
1705 {
1706         const char *prefix = symbol_conf.source_prefix;
1707
1708         if (!prefix) {
1709                 if (raw_path[0] != '/' && comp_dir)
1710                         /* If not an absolute path, try to use comp_dir */
1711                         prefix = comp_dir;
1712                 else {
1713                         if (access(raw_path, R_OK) == 0) {
1714                                 *new_path = strdup(raw_path);
1715                                 return *new_path ? 0 : -ENOMEM;
1716                         } else
1717                                 return -errno;
1718                 }
1719         }
1720
1721         *new_path = malloc((strlen(prefix) + strlen(raw_path) + 2));
1722         if (!*new_path)
1723                 return -ENOMEM;
1724
1725         for (;;) {
1726                 sprintf(*new_path, "%s/%s", prefix, raw_path);
1727
1728                 if (access(*new_path, R_OK) == 0)
1729                         return 0;
1730
1731                 if (!symbol_conf.source_prefix) {
1732                         /* In case of searching comp_dir, don't retry */
1733                         zfree(new_path);
1734                         return -errno;
1735                 }
1736
1737                 switch (errno) {
1738                 case ENAMETOOLONG:
1739                 case ENOENT:
1740                 case EROFS:
1741                 case EFAULT:
1742                         raw_path = strchr(++raw_path, '/');
1743                         if (!raw_path) {
1744                                 zfree(new_path);
1745                                 return -ENOENT;
1746                         }
1747                         continue;
1748
1749                 default:
1750                         zfree(new_path);
1751                         return -errno;
1752                 }
1753         }
1754 }